The present invention relates in general to solid-state lasers and pertains, more particularly, to a microwave-driven (MWD) UV solid-state laser. The laser of this invention provides an efficient, compact, and tunable solid-state laser and is an improvement over the conventional microwave-driven solid-state laser.
With conventional solid-state lasers it is generally necessary to provide a broadband source, such as high-pressure, and high-current rare gas flashlamps for pumping solid-state lasers. This approach can be traced to the initial demonstration of an operable ruby laser in 1960.
In theory, broadband sources should radiate the majority of their energy in the visible to near infra-red. However, the plasma that is produced is optically thick for visible to infrared transmissions due in part to self-absorption and Doppler and pressure broadening. Other drawbacks are well known for the conventional broad-band sources and their various applications.
Narrow-band sources are known as drivers for solid-state lasers. One application of a narrow-band source is the use of a frequency doubled Nd:YAG laser or a dye laser as an excitation source to drive a tunable Ti: Al.sub.2 O.sub.3 laser. Another example of the use of a narrow-band source are the 50% to 60% efficient narrow-band semi-conductor lasers which emit at approximately 810 nm, coupled with fiber optics or coupled to the side of a Nd: YAG rod.
Another drawback associated with the narrow-band semi-conductor lasers is an overall efficiency of converting heat to 810 nm light of only 20%, approximately. Although this is considered relatively efficient, the single semi-conductor lasers will be likely to produce more than 100 milliwatts of continuous power or less.
Therefore, a solid-state laser such as Nd: YAG in which the coupling of the 810 nm light is assumed to be 40% efficient, and which has a 50% efficiency of converting absorbed fluorescence into laser photons, would require at a minimum an array of fifty (50) semi-conductor lasers to produce each watt of solid-state laser output.